CHARACTERIZATION OF THE WEED SEED BANK IN ZERO AND CONVENTIONAL TILLAGE IN CENTRAL CHILE

Abstract

We studied the abundance, species composition, and depth distribution of the weed seed bank under no-tillage (NT) and conventional tillage (CT) at two sites, A and B. Soil samples were taken at three soil depths (0-2, 2-5, and 5-15 cm). Germinated, dormant, and total seeds were counted. The total number of seeds was higher (p <= 0.05) under CT treatment at the two sites (CTA = 5175 seeds m(-2), NTA = 3250 seeds m(-2), CTB = 33 770 m(-2), and NTB = 22 437 seeds m(-2)). The number of viable, dormant, and germinated seeds was also higher (p <= 0.05) in CT at the two sites. The percentage of viable seeds was low with 37% (CTA), 34% (CTB), 21% (NTA), and 8% (NTB). Viable seeds of Chenopodium album L. (CHEAL) dominated in the two trials with 67% (CTA), 20% (NTA), 96% (CTB), and 77% (NTB). In a principal component analysis, PC1 separated viable seeds of weed species according to tillage and PC2 separated weed species according to sites. Poa annua L. was the most important species associated with NT followed by Cichorium intybus L., and Sonchus while Euphorbia helioscopia L. and Echinochloa crus-galli (L.) P. Beauv. were associated with CT.